The present invention relates to a compound recording and reproducing magnetic head having a recording head and a reproducing head which utilizes a magnetoresistive effect element compound therein, and a method for manufacturing the same. More particularly, it relates to a so-called three-legged compound magnetic head which is suitable for use with a magnetic disk unit which uses a plurality of magnetic disks.
Examples of the compound recording and reproducing magnetic head having a recording head and a reproducing head which uses a magnetoresistive effect element integrated therein are shown in U.S. Pat. No. 3,921,217 to Thompson issued on Nov. 18, 1975, U.S. Pat. No. 3,908,194 to Romankiw issued on Sept. 23, 1975, U.S. Pat. No. 3,975,772 to Lin issued on Aug. 17, 1976, JP-A-58-50622 filed in Japan on Sept. 18, 1981 by Mitsubishi Electric Corporation and published on Mar. 25, 1983, and JP-A-59-30223 filed in Japan on June 20, 1983 by International Business Machines Corporation and published on Feb. 17, 1984.
The magnetic disk unit to which the compound magnetic head of the present invention is applied is provided with a compound magnetic head corresponding to each of a plurality of magnetic disks 121, 122 and 123. Those compound magnetic heads 101-104 are positioned to predetermined positions on the rotating magnetic disks 121-123 by a single transport device. As shown in FIG. 2, where the recording heads of the compound magnetic heads 101-104 record data on tracks 131-134 on surfaces W-Z of the magnetic disks by the actuation of the transport means 110, it is necessary to align effective reproducing regions (reproducing gap widths) 161-164 to the recording tracks 131-134 to precisely reproduce the data recorded on the recording tracks 131-134.
However, if the recording gaps and the reproducing gaps 161-164 have deviations .delta..sub.1 -.delta..sub.4 for each of the compound magnetic heads 101-104 as shown in FIG. 2, it is necessary to sequentially move the reproducing heads 161-164 to precisely align to the recording tracks in accordance with the respective deviations .delta..sub.1 -.delta..sub.4 in order to precisely read the series of data of the tracks 131-134. As a result, a long transport time is required before the reproduction is started. Because of a trend of high recording density in a recent magnetic disk unit, the track width is very narrow, for example 6-20 .mu.m, and it must be aligned within a range which is no larger than 5-10% of the effective width. Thus, high precision positioning is required.
None of the references cited above teaches a relative positional relationship between the recording head and the reproducing head of the compound head.